1
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Zhao T, Pan Y. Transformation of β-sheets into disordered structures during the fossilization of feathers. Nat Ecol Evol 2024:10.1038/s41559-024-02432-6. [PMID: 38867091 DOI: 10.1038/s41559-024-02432-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 05/08/2024] [Indexed: 06/14/2024]
Affiliation(s)
- Tao Zhao
- Institute of Palaeontology, Yunnan Key Laboratory of Earth System Science, Yunnan University, Kunming, China.
| | - Yanhong Pan
- State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Centre for Research and Education on Biological Evolution and Environment, Frontiers Science Center for Critical Earth Material Cycling, Nanjing University, Nanjing, China
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2
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Slater TS, Ito S, Wakamatsu K, Zhang F, Sjövall P, Jarenmark M, Lindgren J, McNamara ME. Taphonomic experiments reveal authentic molecular signals for fossil melanins and verify preservation of phaeomelanin in fossils. Nat Commun 2023; 14:5651. [PMID: 37803012 PMCID: PMC10558522 DOI: 10.1038/s41467-023-40570-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/01/2023] [Indexed: 10/08/2023] Open
Abstract
Melanin pigments play a critical role in physiological processes and shaping animal behaviour. Fossil melanin is a unique resource for understanding the functional evolution of melanin but the impact of fossilisation on molecular signatures for eumelanin and, especially, phaeomelanin is not fully understood. Here we present a model for the chemical taphonomy of fossil eumelanin and phaeomelanin based on thermal maturation experiments using feathers from extant birds. Our results reveal which molecular signatures are authentic signals for thermally matured eumelanin and phaeomelanin, which signatures are artefacts derived from the maturation of non-melanin molecules, and how these chemical data are impacted by sample preparation. Our model correctly predicts the molecular composition of eumelanins in diverse vertebrate fossils from the Miocene and Cretaceous and, critically, identifies direct molecular evidence for phaeomelanin in these fossils. This taphonomic framework adds to the geochemical toolbox that underpins reconstructions of melanin evolution and of melanin-based coloration in fossil vertebrates.
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Affiliation(s)
- Tiffany S Slater
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
- Environmental Research Institute, University College Cork, Cork, Ireland.
| | - Shosuke Ito
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Aichi, Japan
| | - Kazumasa Wakamatsu
- Institute for Melanin Chemistry, Fujita Health University, Toyoake, Aichi, Japan
| | - Fucheng Zhang
- Institute of Geology and Paleontology, Linyi University, Linyi City, Shandong, China
| | - Peter Sjövall
- RISE Research Institutes of Sweden, Materials and Production, 501 15, Borås, Sweden
| | | | - Johan Lindgren
- Department of Geology, Lund University, 223 62, Lund, Sweden
| | - Maria E McNamara
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.
- Environmental Research Institute, University College Cork, Cork, Ireland.
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3
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Anderson LA. Biomolecular histology as a novel proxy for ancient DNA and protein sequence preservation. Ecol Evol 2022; 12:e9518. [PMCID: PMC9743065 DOI: 10.1002/ece3.9518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Revised: 10/03/2022] [Accepted: 10/17/2022] [Indexed: 12/14/2022] Open
Abstract
Researchers' ability to accurately screen fossil and subfossil specimens for preservation of DNA and protein sequences remains limited. Thermal exposure and geologic age are usable proxies for sequence preservation on a broad scale but are of nominal use for specimens of similar depositional environments. Cell and tissue biomolecular histology is thus proposed as a novel proxy for determining sequence preservation potential of ancient specimens with improved accuracy. Biomolecular histology as a proxy is hypothesized to elucidate why fossils/subfossils of some depositional environments preserve sequences while others do not and to facilitate selection of ancient specimens for use in molecular studies.
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Affiliation(s)
- Landon A. Anderson
- Department of BiologyNorth Carolina State UniversityRaleighNorth CarolinaUSA
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4
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Environmental Factors Affecting Feather Taphonomy. BIOLOGY 2022; 11:biology11050703. [PMID: 35625431 PMCID: PMC9138376 DOI: 10.3390/biology11050703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022]
Abstract
The exceptional preservation of feathers in the fossil record has led to a better understanding of both phylogeny and evolution. Here we address factors that may have contributed to the preservation of feathers in ancient organisms using experimental taphonomy. We show that the atmospheres of the Mesozoic, known to be elevated in both CO2 and with temperatures above present levels, may have contributed to the preservation of these soft tissues by facilitating rapid precipitation of hydroxy- or carbonate hydroxyapatite, thus outpacing natural degradative processes. Data also support that that microbial degradation was enhanced in elevated CO2, but mineral deposition was also enhanced, contributing to preservation by stabilizing the organic components of feathers.
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5
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Tahoun M, Engeser M, Namasivayam V, Sander PM, Müller CE. Chemistry and Analysis of Organic Compounds in Dinosaurs. BIOLOGY 2022; 11:670. [PMID: 35625398 PMCID: PMC9138232 DOI: 10.3390/biology11050670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/12/2022] [Accepted: 04/22/2022] [Indexed: 11/17/2022]
Abstract
This review provides an overview of organic compounds detected in non-avian dinosaur fossils to date. This was enabled by the development of sensitive analytical techniques. Non-destructive methods and procedures restricted to the sample surface, e.g., light and electron microscopy, infrared (IR) and Raman spectroscopy, as well as more invasive approaches including liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), time-of-flight secondary ion mass spectrometry, and immunological methods were employed. Organic compounds detected in samples of dinosaur fossils include pigments (heme, biliverdin, protoporphyrin IX, melanin), and proteins, such as collagens and keratins. The origin and nature of the observed protein signals is, however, in some cases, controversially discussed. Molecular taphonomy approaches can support the development of suitable analytical methods to confirm reported findings and to identify further organic compounds in dinosaur and other fossils in the future. The chemical properties of the various organic compounds detected in dinosaurs, and the techniques utilized for the identification and analysis of each of the compounds will be discussed.
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Affiliation(s)
- Mariam Tahoun
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, University of Bonn, D-53121 Bonn, Germany; (M.T.); (V.N.)
| | - Marianne Engeser
- Kekulé Institute for Organic Chemistry and Biochemistry, University of Bonn, D-53121 Bonn, Germany;
| | - Vigneshwaran Namasivayam
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, University of Bonn, D-53121 Bonn, Germany; (M.T.); (V.N.)
| | - Paul Martin Sander
- Institute of Geosciences, Section Paleontology, University of Bonn, D-53113 Bonn, Germany;
| | - Christa E. Müller
- PharmaCenter Bonn, Pharmaceutical Institute, Pharmaceutical & Medicinal Chemistry, University of Bonn, D-53121 Bonn, Germany; (M.T.); (V.N.)
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6
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Hendrickx C, Bell PR, Pittman M, Milner ARC, Cuesta E, O'Connor J, Loewen M, Currie PJ, Mateus O, Kaye TG, Delcourt R. Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs. Biol Rev Camb Philos Soc 2022; 97:960-1004. [PMID: 34991180 DOI: 10.1111/brv.12829] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/10/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022]
Abstract
Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian-like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non-feathered integumentary structures in non-avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non-averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non-scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non-avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake-like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co-occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.
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Affiliation(s)
- Christophe Hendrickx
- Unidad Ejecutora Lillo, CONICET-Fundación Miguel Lillo, 251 Miguel Lillo, San Miguel de Tucumán, Tucumán, 4000, Argentina
| | - Phil R Bell
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Michael Pittman
- Vertebrate Palaeontology Laboratory, Department of Earth Sciences, The University of Hong Kong, Pokfulam, Hong Kong, SAR, China.,Department of Earth Sciences, University College London, WC1E 6BT, United Kingdom
| | - Andrew R C Milner
- St. George Dinosaur Discovery Site at Johnson Farm, 2180 East Riverside Drive, St. George, UT, U.S.A
| | - Elena Cuesta
- Bayerische Staatssammlung für Paläontologie und Geologie, Richard-Wagner-Str. 10, Munich, 80333, Germany
| | - Jingmai O'Connor
- Field Museum of Natural History, 1400 S Lake Shore Drive, Chicago, IL, 60605, U.S.A
| | - Mark Loewen
- Department of Geology and Geophysics, University of Utah, Frederick Albert Sutton Building, 115 South 1460 East, Salt Lake City, UT, 84112, U.S.A.,Natural History Museum of Utah, 301 Wakara Way, Salt Lake City, UT, 84108, U.S.A
| | - Philip J Currie
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Octávio Mateus
- GeoBioTec, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.,Museu da Lourinhã, 95 Rua João Luis de Moura, Lourinhã, 2530-158, Portugal
| | - Thomas G Kaye
- Foundation for Scientific Advancement, 7023 Alhambra Dr., Sierra Vista, AZ, 85650, U.S.A
| | - Rafael Delcourt
- Universidade Estadual de Campinas (UNICAMP), Instituto de Geociências, Cidade Universitária, Rua Carlos Gomes, 250, Campinas, SP, 13083-855, Brazil
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7
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Carney RM, Tischlinger H, Shawkey MD. Evidence corroborates identity of isolated fossil feather as a wing covert of Archaeopteryx. Sci Rep 2020; 10:15593. [PMID: 32999314 PMCID: PMC7528088 DOI: 10.1038/s41598-020-65336-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 05/01/2020] [Indexed: 11/24/2022] Open
Abstract
The historic fossil feather from the Jurassic Solnhofen has played a pivotal but controversial role in our evolutionary understanding of dinosaurs and birds. Recently, a study confirmed the diagnostic morphology of the feather’s original calamus, but nonetheless challenged the proposed identity as an Archaeopteryx covert. However, there are errors in the results and interpretations presented. Here we show that the feather is most likely an upper major primary covert, based on its long calamus (23.3% total length) and eight other anatomical attributes. Critically, this hypothesis is independently supported by evidence of similar primary coverts in multiple specimens of Archaeopteryx–including from the same fossil site and horizon as the isolated feather. We also provide additional insights, such as an updated colour reconstruction of the entire feather as matte black, with 90% probability. Given the isolated nature of the fossil feather, we can never know the anatomical and taxonomic provenance with 100% certainty. However, based on all available evidence, the most empirical and parsimonious conclusion is that this feather represents a primary covert from the ancient wing of Archaeopteryx.
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Affiliation(s)
- Ryan M Carney
- Department of Integrative Biology, University of South Florida, 33620, Tampa, FL, USA.
| | | | - Matthew D Shawkey
- Evolution and Optics of Nanostructures Group, Department of Biology, University of Ghent, 9000, Ghent, Belgium
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8
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Molecular tests support the viability of rare earth elements as proxies for fossil biomolecule preservation. Sci Rep 2020; 10:15566. [PMID: 32968129 PMCID: PMC7511940 DOI: 10.1038/s41598-020-72648-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 08/13/2020] [Indexed: 11/22/2022] Open
Abstract
The rare earth element (REE) composition of a fossil bone reflects its chemical alteration during diagenesis. Consequently, fossils presenting low REE concentrations and/or REE profiles indicative of simple diffusion, signifying minimal alteration, have been proposed as ideal candidates for paleomolecular investigation. We directly tested this prediction by conducting multiple biomolecular assays on a well-preserved fibula of the dinosaur Edmontosaurus from the Cretaceous Hell Creek Formation previously found to exhibit low REE concentrations and steeply-declining REE profiles. Gel electrophoresis identified the presence of organic material in this specimen, and subsequent immunofluorescence and enzyme-linked immunosorbant assays identified preservation of epitopes of the structural protein collagen I. Our results thereby support the utility of REE profiles as proxies for soft tissue and biomolecular preservation in fossil bones. Based on considerations of trace element taphonomy, we also draw predictions as to the biomolecular recovery potential of additional REE profile types exhibited by fossil bones.
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9
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Hierarchical biota-level and taxonomic controls on the chemistry of fossil melanosomes revealed using synchrotron X-ray fluorescence. Sci Rep 2020; 10:8970. [PMID: 32488139 PMCID: PMC7265528 DOI: 10.1038/s41598-020-65868-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 05/12/2020] [Indexed: 12/22/2022] Open
Abstract
Fossil melanosomes, micron-sized granules rich in melanin in vivo, provide key information for investigations of the original coloration, taxonomy and internal anatomy of fossil vertebrates. Such studies rely, in part, on analysis of the inorganic chemistry of preserved melanosomes and an understanding of melanosome chemical taphonomy. The extent to which the preserved chemistry of fossil melanosomes is biased by biotic and abiotic factors is, however, unknown. Here we report the discovery of hierarchical controls on the inorganic chemistry of melanosomes from fossil vertebrates from nine biotas. The chemical data are dominated by a strong biota-level signal, indicating that the primary taphonomic control is the diagenetic history of the host sediment. This extrinsic control is superimposed by a biological, tissue-level control; tissue-specific chemical variation is most likely to survive in fossils where the inorganic chemistry of preserved melanosomes is distinct from that of the host sediment. Comparative analysis of our data for fossil and modern amphibians reveals that most fossil specimens show tissue-specific melanosome chemistries that differ from those of extant analogues, strongly suggesting alteration of original melanosome chemistry. Collectively, these findings form a predictive tool for the identification of fossil deposits with well-preserved melanosomes amenable to studies of fossil colour and anatomy.
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10
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Slater TS, McNamara ME, Orr PJ, Foley TB, Ito S, Wakamatsu K. Taphonomic experiments resolve controls on the preservation of melanosomes and keratinous tissues in feathers. PALAEONTOLOGY 2020; 63:103-115. [PMID: 32025055 PMCID: PMC6988486 DOI: 10.1111/pala.12445] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 05/15/2019] [Indexed: 06/10/2023]
Abstract
Fossils are a key source of data on the evolution of feather structure and function through deep time, but their ability to resolve macroevolutionary questions is compromised by an incomplete understanding of their taphonomy. Critically, the relative preservation potential of two key feather components, melanosomes and keratinous tissue, is not fully resolved. Recent studies suggesting that melanosomes are preferentially preserved conflict with observations that melanosomes preserve in fossil feathers as external moulds in an organic matrix. To date, there is no model to explain the latter mode of melanosome preservation. We addressed these issues by degrading feathers in systematic taphonomic experiments incorporating decay, maturation and oxidation in isolation and combination. Our results reveal that the production of mouldic melanosomes requires interactions with an oxidant and is most likely to occur prior to substantial maturation. This constrains the taphonomic conditions under which melanosomes are likely to be fossilized. Critically, our experiments also confirm that keratinous feather structures have a higher preservation potential than melanosomes under a range of diagenetic conditions, supporting hitherto controversial hypotheses that fossil feathers can retain degraded keratinous structures.
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Affiliation(s)
- Tiffany S. Slater
- School of Biological, Earth & Environmental SciencesUniversity College CorkCorkIreland
| | - Maria E. McNamara
- School of Biological, Earth & Environmental SciencesUniversity College CorkCorkIreland
| | - Patrick J. Orr
- UCDSchool of Earth SciencesUniversity College DublinDublinIreland
| | - Tara B. Foley
- Department of Anatomy & NeuroscienceUniversity College CorkCorkIreland
| | - Shosuke Ito
- Department of ChemistryFujita Health University School of Health SciencesToyoakeAichiJapan
| | - Kazumasa Wakamatsu
- Department of ChemistryFujita Health University School of Health SciencesToyoakeAichiJapan
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11
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Filamentous Integuments in Nonavialan Theropods and Their Kin: Advances and Future Perspectives for Understanding the Evolution of Feathers. THE EVOLUTION OF FEATHERS 2020. [DOI: 10.1007/978-3-030-27223-4_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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12
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Abstract
Introduction: Despite an extensive published literature, skepticism over the claim of original biochemicals including proteins preserved in the fossil record persists and the issue remains controversial. Workers using many different techniques including mass spectrometry, X-ray, electron microscopy and optical spectroscopic techniques, have attempted to verify proteinaceous or other biochemicals that appear endogenous to fossils found throughout the geologic column.Areas covered: This paper presents a review of the relevant literature published over the last 50 years. A comparative survey of the reported techniques used is also given.Expert opinion: Morphological and molecular investigations show that original biochemistry is geologically extensive, geographically global, and taxonomically wide-ranging. The survival of endogenous organics in fossils remains the subject of widespread and increasing research investigation.
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Affiliation(s)
- Brian Thomas
- Mass Spectrometry Group, Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, UK
| | - Stephen Taylor
- Mass Spectrometry Group, Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, UK
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13
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Pinheiro FL, Prado G, Ito S, Simon JD, Wakamatsu K, Anelli LE, Andrade JAF, Glass K. Chemical characterization of pterosaur melanin challenges color inferences in extinct animals. Sci Rep 2019; 9:15947. [PMID: 31685890 PMCID: PMC6828676 DOI: 10.1038/s41598-019-52318-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 10/11/2019] [Indexed: 12/18/2022] Open
Abstract
Melanosomes (melanin-bearing organelles) are common in the fossil record occurring as dense packs of globular microbodies. The organic component comprising the melanosome, melanin, is often preserved in fossils, allowing identification of the chemical nature of the constituent pigment. In present-day vertebrates, melanosome morphology correlates with their pigment content in selected melanin-containing structures, and this interdependency is employed in the color reconstruction of extinct animals. The lack of analyses integrating the morphology of fossil melanosomes with the chemical identification of pigments, however, makes these inferences tentative. Here, we chemically characterize the melanin content of the soft tissue headcrest of the pterosaur Tupandactylus imperator by alkaline hydrogen peroxide oxidation followed by high-performance liquid chromatography. Our results demonstrate the unequivocal presence of eumelanin in T. imperator headcrest. Scanning electron microscopy followed by statistical analyses, however, reveal that preserved melanosomes containing eumelanin are undistinguishable to pheomelanin-bearing organelles of extant vertebrates. Based on these new findings, straightforward color inferences based on melanosome morphology may not be valid for all fossil vertebrates, and color reconstructions based on ultrastructure alone should be regarded with caution.
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Affiliation(s)
- Felipe L Pinheiro
- Laboratório de Paleobiologia, Universidade Federal do Pampa, São Gabriel, 97300-162, Brazil.
| | - Gustavo Prado
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil.
| | - Shosuke Ito
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | | | - Kazumasa Wakamatsu
- Department of Chemistry, Fujita Health University School of Medical Sciences, Toyoake, Aichi, 470-1192, Japan
| | - Luiz E Anelli
- Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazil
| | - José A F Andrade
- Centro de Pesquisas Paleontológicas da Chapada do Araripe, Departamento Nacional de Produção Mineral, 63100-440, Crato, Brazil
| | - Keely Glass
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
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14
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Schweitzer MH, Schroeter ER, Cleland TP, Zheng W. Paleoproteomics of Mesozoic Dinosaurs and Other Mesozoic Fossils. Proteomics 2019; 19:e1800251. [PMID: 31172628 DOI: 10.1002/pmic.201800251] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 05/07/2019] [Indexed: 12/20/2022]
Abstract
Molecular studies have contributed greatly to our understanding of evolutionary processes that act upon virtually every aspect of living organisms. However, these studies are limited with regard to extinct organisms, particularly those from the Mesozoic because fossils pose unique challenges to molecular workflows, and because prevailing wisdom suggests no endogenous molecular components can persist into deep time. Here, the power and potential of a molecular approach to Mesozoic fossils is discussed. Molecular methods that have been applied to Mesozoic fossils-including iconic, non-avian dinosaurs- and the challenges inherent in such analyses, are compared and evaluated. Taphonomic processes resulting in the transition of living organisms from the biosphere into the fossil record are reviewed, and the possible effects of taphonomic alteration on downstream analyses that can be problematic for very old material (e.g., molecular modifications, limitations of on comparative databases) are addressed. Molecular studies applied to ancient remains are placed in historical context, and past and current studies are evaluated with respect to producing phylogenetically and/or evolutionarily significant data. Finally, some criteria for assessing the presence of endogenous biomolecules in very ancient fossil remains are suggested as a starting framework for such studies.
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Affiliation(s)
- Mary Higby Schweitzer
- Department of Biological Sciences, North Carolina State University, Raleigh, 27695, NC.,North Carolina Museum of Natural Sciences, Raleigh, NC.,Museum of the Rockies, Montana State University, Bozeman, MT.,Department of Geology, Lund University, Sölvegatan 12, SE-223 62, Lund, Sweden
| | - Elena R Schroeter
- Department of Biological Sciences, North Carolina State University, Raleigh, 27695, NC
| | - Timothy P Cleland
- Museum Conservation Institute, Smithsonian Institution, Suitland, 20746, MD
| | - Wenxia Zheng
- Department of Biological Sciences, North Carolina State University, Raleigh, 27695, NC
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15
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Brejcha J, Bataller JV, Bosáková Z, Geryk J, Havlíková M, Kleisner K, Maršík P, Font E. Body coloration and mechanisms of colour production in Archelosauria: the case of deirocheline turtles. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190319. [PMID: 31417734 PMCID: PMC6689573 DOI: 10.1098/rsos.190319] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/28/2019] [Indexed: 05/11/2023]
Abstract
Animal body coloration is a complex trait resulting from the interplay of multiple mechanisms. While many studies address the functions of animal coloration, the mechanisms of colour production still remain unknown in most taxa. Here we compare reflectance spectra, cellular, ultra- and nano-structure of colour-producing elements, and pigment types in two freshwater turtles with contrasting courtship behaviour, Trachemys scripta and Pseudemys concinna. The two species differ in the distribution of pigment cell-types and in pigment diversity. We found xanthophores, melanocytes, abundant iridophores and dermal collagen fibres in stripes of both species. The yellow chin and forelimb stripes of both P. concinna and T. scripta contain xanthophores and iridophores, but the post-orbital regions of the two species differ in cell-type distribution. The yellow post-orbital region of P. concinna contains both xanthophores and iridophores, while T. scripta has only xanthophores in the yellow-red postorbital/zygomatic regions. Moreover, in both species, the xanthophores colouring the yellow-red skin contain carotenoids, pterins and riboflavin, but T. scripta has a higher diversity of pigments than P. concinna. Trachemys s. elegans is sexually dichromatic. Differences in the distribution of pigment cell types across body regions in the two species may be related to visual signalling but do not match predictions based on courtship position. Our results demonstrate that archelosaurs share some colour production mechanisms with amphibians and lepidosaurs (i.e. vertical layering/stacking of different pigment cell types and interplay of carotenoids and pterins), but also employ novel mechanisms (i.e. nano-organization of dermal collagen) shared with mammals.
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Affiliation(s)
- Jindřich Brejcha
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
- Department of Zoology, Natural History Museum, National Museum, Václavské nám. 68, Prague 1, 110 00, Czech Republic
- Department of Biophysical Chemistry, J. Heyrovský Institute of Physical Chemistry of the Czech Academy of Sciences, Dolejškova 3, Prague 8, 18223, Czech Republic
| | - José Vicente Bataller
- Centro de Conservación de Especies Dulceacuícolas de la Comunidad Valenciana. VAERSA-Generalitat Valenciana, El Palmar, València, 46012, Spain
| | - Zuzana Bosáková
- Department of Analytical Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2, 128 43, Czech Republic
| | - Jan Geryk
- Department of Biology and Medical Genetics, 2nd Faculty of Medicine, Charles University and University Hospital Motol, V Úvalu 84, 150 06 Prague, Czech Republic
| | - Martina Havlíková
- Department of Analytical Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2, 128 43, Czech Republic
| | - Karel Kleisner
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Viničná 7, Prague 2, 128 00, Czech Republic
| | - Petr Maršík
- Department of Food Science, Faculty of Agrobiology, Food, and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, Prague 6, 165 00, Czech Republic
| | - Enrique Font
- Ethology Lab, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, C/ Catedrátic José Beltrán Martinez 2, Paterna, València, 46980, Spain
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16
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Combined microscopy and spectroscopy techniques to characterize a fossilized feather with minimal damage to the specimen. Micron 2019; 120:17-24. [DOI: 10.1016/j.micron.2019.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 11/20/2022]
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17
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Yang Z, Jiang B, McNamara ME, Kearns SL, Pittman M, Kaye TG, Orr PJ, Xu X, Benton MJ. Pterosaur integumentary structures with complex feather-like branching. Nat Ecol Evol 2018; 3:24-30. [DOI: 10.1038/s41559-018-0728-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 10/23/2018] [Indexed: 01/24/2023]
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18
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Schweitzer MH, Zheng W, Moyer AE, Sjövall P, Lindgren J. Preservation potential of keratin in deep time. PLoS One 2018; 13:e0206569. [PMID: 30485294 PMCID: PMC6261410 DOI: 10.1371/journal.pone.0206569] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 10/16/2018] [Indexed: 11/18/2022] Open
Abstract
Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the β-keratin that comprises feathers, has potential to preserve in fossil remains.
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Affiliation(s)
- Mary Higby Schweitzer
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
- North Carolina Museum of Natural Sciences, Raleigh, North Carolina, United States of America
- Department of Geology, Lund University, Lund, Sweden
| | - Wenxia Zheng
- Department of Biological Sciences, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Alison E. Moyer
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Peter Sjövall
- RISE Research Institutes of Sweden, Chemistry and Materials, Borås, Sweden
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19
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Li Q, Clarke JA, Gao KQ, Peteya JA, Shawkey MD. Elaborate plumage patterning in a Cretaceous bird. PeerJ 2018; 6:e5831. [PMID: 30405969 PMCID: PMC6216952 DOI: 10.7717/peerj.5831] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 09/21/2018] [Indexed: 11/20/2022] Open
Abstract
Integumentary patterns and colors can differentiate species, sexes, and life changes and can inform on habitat and ecology. However, they are rarely preserved in the fossil record. Here, we report on an extremely well-preserved specimen of the Cretaceous bird Confuciusornis with unprecedented complexity, including small spots on the wings, crest, and throat. Morphological and chemical evidence suggest that these patterns are produced by melanin, but unusual preservation prevents assignment of specific colors. Based on comparisons with extant birds, these patterns were likely used for camouflage, although other functions including sexual signaling cannot be ruled out. Our data show that even more elaborate plumage patterns than the spangles in Anchiornis and stripes in Sinosauropteryx were present at a relatively early stage of avian evolution, showing the significance of coloration and patterning to feather evolution.
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Affiliation(s)
- Quanguo Li
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China
| | - Julia A Clarke
- Jackson School of Geosciences, University of Texas at Austin, Austin, TX, USA
| | - Ke-Qin Gao
- School of Earth and Space Sciences, Peking University, Beijing, China
| | | | - Matthew D Shawkey
- Evolution and Optics of Nanostructures Group, Department of Biology, University of Ghent, Belgium
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20
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A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution. Nat Commun 2018; 9:217. [PMID: 29335537 PMCID: PMC5768872 DOI: 10.1038/s41467-017-02515-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 12/05/2017] [Indexed: 12/25/2022] Open
Abstract
The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and particularly of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies. Here we report a distinctive new Yanliao theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm and leg feathers than Anchiornis and tail feathers with asymmetrical vanes forming a tail surface area even larger than that in Archaeopteryx. Nanostructures, interpreted as melanosomes, are morphologically similar to organized, platelet-shaped organelles that produce bright iridescent colours in extant birds. The new species indicates the presence of bony ornaments, feather colour and flight-related features consistent with proposed rapid character evolution and significant diversity in signalling and locomotor strategies near bird origins. A number of paravian dinosaurs have been described from the Jurassic Yanliao biota, but these have tended to be morphologically similar to Archaeopteryx. Here, Hu. describe the new paravian dinosaur, Caihong juji gen. et sp. nov., which possesses a suite of unusual skeletal and feather characteristics.
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21
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Prondvai E, Godefroit P, Adriaens D, Hu DY. Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs. Sci Rep 2018; 8:258. [PMID: 29321475 PMCID: PMC5762864 DOI: 10.1038/s41598-017-18218-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 12/06/2017] [Indexed: 12/30/2022] Open
Abstract
With their elongated forelimbs and variable aerial skills, paravian dinosaurs, a clade also comprising modern birds, are in the hotspot of vertebrate evolutionary research. Inferences on the early evolution of flight largely rely on bone and feather morphology, while osteohistological traits are usually studied to explore life-history characteristics. By sampling and comparing multiple homologous fore- and hind limb elements, we integrate for the first time qualitative and quantitative osteohistological approaches to get insight into the intraskeletal growth dynamics and their functional implications in five paravian dinosaur taxa, Anchiornis, Aurornis, Eosinopteryx, Serikornis, and Jeholornis. Our qualitative assessment implies a considerable diversity in allometric/isometric growth patterns among these paravians. Quantitative analyses show that neither taxa nor homologous elements have characteristic histology, and that ontogenetic stage, element size and the newly introduced relative element precocity only partially explain the diaphyseal histovariability. Still, Jeholornis, the only avialan studied here, is histologically distinct from all other specimens in the multivariate visualizations raising the hypothesis that its bone tissue characteristics may be related to its superior aerial capabilities compared to the non-avialan paravians. Our results warrant further research on the osteohistological correlates of flight and developmental strategies in birds and bird-like dinosaurs.
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Affiliation(s)
- Edina Prondvai
- Evolutionary Morphology of Vertebrates, Department of Biology, Ghent University, Ghent, Belgium.
| | - Pascal Godefroit
- Royal Belgian Institute of Natural Sciences, Directorate 'Earth and History of Life', Brussels, Belgium
| | - Dominique Adriaens
- Evolutionary Morphology of Vertebrates, Department of Biology, Ghent University, Ghent, Belgium
| | - Dong-Yu Hu
- Paleontological Institute, Shenyang Normal University, Key Laboratory for Evolution of Past Life in Northeast Asia, Ministry of Land and Resources, Shenyang, China
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22
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Biochemistry and adaptive colouration of an exceptionally preserved juvenile fossil sea turtle. Sci Rep 2017; 7:13324. [PMID: 29042651 PMCID: PMC5645316 DOI: 10.1038/s41598-017-13187-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 09/19/2017] [Indexed: 12/27/2022] Open
Abstract
The holotype (MHM-K2) of the Eocene cheloniine Tasbacka danica is arguably one of the best preserved juvenile fossil sea turtles on record. Notwithstanding compactional flattening, the specimen is virtually intact, comprising a fully articulated skeleton exposed in dorsal view. MHM-K2 also preserves, with great fidelity, soft tissue traces visible as a sharply delineated carbon film around the bones and marginal scutes along the edge of the carapace. Here we show that the extraordinary preservation of the type of T. danica goes beyond gross morphology to include ultrastructural details and labile molecular components of the once-living animal. Haemoglobin-derived compounds, eumelanic pigments and proteinaceous materials retaining the immunological characteristics of sauropsid-specific β-keratin and tropomyosin were detected in tissues containing remnant melanosomes and decayed keratin plates. The preserved organics represent condensed remains of the cornified epidermis and, likely also, deeper anatomical features, and provide direct chemical evidence that adaptive melanism – a biological means used by extant sea turtle hatchlings to elevate metabolic and growth rates – had evolved 54 million years ago.
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23
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A new Jurassic theropod from China documents a transitional step in the macrostructure of feathers. Naturwissenschaften 2017; 104:74. [PMID: 28831510 DOI: 10.1007/s00114-017-1496-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 04/13/2017] [Accepted: 08/03/2017] [Indexed: 10/19/2022]
Abstract
Genuine fossils with exquisitely preserved plumage from the Late Jurassic and Early Cretaceous of northeastern China have recently revealed that bird-like theropod dinosaurs had long pennaceous feathers along their hindlimbs and may have used their four wings to glide or fly. Thus, it has been postulated that early bird flight might initially have involved four wings (Xu et al. Nature 421:335-340, 2003; Hu et al. Nature 461:640-643, 2009; Han et al. Nat Commun 5:4382, 2014). Here, we describe Serikornis sungei gen. et sp. nov., a new feathered theropod from the Tiaojishan Fm (Late Jurassic) of Liaoning Province, China. Its skeletal morphology suggests a ground-dwelling ecology with no flying adaptations. Our phylogenetic analysis places Serikornis, together with other Late Jurassic paravians from China, as a basal paravians, outside the Eumaniraptora clade. The tail of Serikornis is covered proximally by filaments and distally by slender rectrices. Thin symmetrical remiges lacking barbules are attached along its forelimbs and elongate hindlimb feathers extend up to its toes, suggesting that hindlimb remiges evolved in ground-dwelling maniraptorans before being co-opted to an arboreal lifestyle or flight.
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24
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Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis. Proc Natl Acad Sci U S A 2016; 113:E7900-E7907. [PMID: 27872291 DOI: 10.1073/pnas.1617168113] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody-antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils.
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25
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26
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Prado GMEM, Anelli LE, Petri S, Romero GR. New occurrences of fossilized feathers: systematics and taphonomy of the Santana Formation of the Araripe Basin (Cretaceous), NE, Brazil. PeerJ 2016; 4:e1916. [PMID: 27441102 PMCID: PMC4941790 DOI: 10.7717/peerj.1916] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 03/18/2016] [Indexed: 12/02/2022] Open
Abstract
Here we describe three fossil feathers from the Early Cretaceous Santana Formation of the Araripe Basin, Brazil. Feathers are the most complex multiform vertebrate integuments; they perform different functions, occurring in both avian and non-avian dinosaurs. Despite their rarity, fossil feathers have been found across the world. Most of the Brazilian feather fossil record comes from the Santana Formation. This formation is composed of two members: Crato (lake) and Romualdo (lagoon); both of which are predominantly reduced deposits, precluding bottom dwelling organisms, resulting in exceptional preservation of the fossils. Despite arid and hot conditions during the Cretaceous, life teemed in the adjacency of this paleolake. Feathered non-avian dinosaurs have not yet been described from the Crato Member, even though there are suggestions of their presence in nearby basins. Our description of the three feathers from the Crato laminated limestone reveals that, despite the small sample size, they can be referred to coelurosaurian theropods. Moreover, based on comparisons with extant feather morphotypes they can be identified as one contour feather and two downy feathers. Despite their rareness and low taxonomic potential, fossilized feathers can offer insights about the paleobiology of its owners and the paleoecology of the Araripe Basin.
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Affiliation(s)
- Gustavo M E M Prado
- Departamento de Geologia Sedimentar e Ambiental, Universidade de São Paulo, São Paulo, Brasil; Programa de Pós-Graduação em Gequímica e Geotectônica, Instituto de Geociências, Universidade de São Paulo, São Paulo, Brasil
| | - Luiz Eduardo Anelli
- Departamento de Geologia Sedimentar e Ambiental, Universidade de São Paulo , São Paulo , Brasil
| | - Setembrino Petri
- Departamento de Geologia Sedimentar e Ambiental, Universidade de São Paulo , São Paulo , Brasil
| | - Guilherme Raffaeli Romero
- Departamento de Geologia Sedimentar e Ambiental, Universidade de São Paulo, São Paulo, Brasil; Programa de Pós-Graduação em Gequímica e Geotectônica, Instituto de Geociências, Universidade de São Paulo, São Paulo, Brasil
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27
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Moyer AE, Zheng W, Schweitzer MH. Keratin Durability Has Implications for the Fossil Record: Results from a 10 Year Feather Degradation Experiment. PLoS One 2016; 11:e0157699. [PMID: 27384819 PMCID: PMC4934732 DOI: 10.1371/journal.pone.0157699] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 05/03/2016] [Indexed: 11/19/2022] Open
Abstract
Keratinous ‘soft tissue’ structures (i.e. epidermally derived and originally non-biomineralized), include feathers, skin, claws, beaks, and hair. Despite their relatively common occurrence in the fossil record (second only to bone and teeth), few studies have addressed natural degradation processes that must occur in all organic material, including those keratinous structures that are incorporated into the rock record as fossils. Because feathers have high preservation potential and strong phylogenetic signal, in the current study we examine feathers subjected to different burial environments for a duration of ~10 years, using transmission electron microscopy (TEM) and in situ immunofluorescence (IF). We use morphology and persistence of specific immunoreactivity as indicators of preservation at the molecular and microstructural levels. We show that feather keratin is durable, demonstrates structural and microstructural integrity, and retains epitopes suitable for specific antibody recognition in even the harshest conditions. These data support the hypothesis that keratin antibody reactivity can be used to identify the nature and composition of epidermal structures in the rock record, and to address evolutionary questions by distinguishing between alpha- (widely distributed) and beta- (limited to sauropsids) keratin.
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Affiliation(s)
- Alison E. Moyer
- Department of Biological Science, North Carolina State University, Raleigh NC 27695, United States of America
- * E-mail:
| | - Wenxia Zheng
- Department of Biological Science, North Carolina State University, Raleigh NC 27695, United States of America
| | - Mary H. Schweitzer
- Department of Biological Science, North Carolina State University, Raleigh NC 27695, United States of America
- North Carolina Museum of Natural Sciences, Raleigh NC 27601, United States of America
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Vinther J. Fossil melanosomes or bacteria? A wealth of findings favours melanosomes: Melanin fossilises relatively readily, bacteria rarely, hence the need for clarification in the debate over the identity of microbodies in fossil animal specimens. Bioessays 2015; 38:220-5. [PMID: 26692172 DOI: 10.1002/bies.201500168] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The discovery of fossil melanosomes has resulted in a wealth of research over the last 7 years, notably the reconstruction of colour in dinosaurs and fossil mammals. In spite of these discoveries some authors persist in arguing that the observed microbodies could represent preserved bacteria. They contend that bacteria fossilise easily and everywhere, which means that one can never be certain that a microbody is a melanosome without an extraordinary burden of evidence. However, this critique mischaracterises the morphological and structural evidence for interpreting microbodies as fossil melanosomes, and hence the basis for using them in reconstructing prehistoric colours. The claims for bacterial omnipresence in the fossil record are themselves not supported, thus tipping the scales strongly towards melanosomes in the bacteria-versus-melanosome controversy.
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Affiliation(s)
- Jakob Vinther
- Schools of Earth Sciences and Biological Sciences, Life Sciences Building University of Bristol, Bristol, United Kingdom
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29
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Schweitzer MH, Lindgren J, Moyer AE. Melanosomes and ancient coloration re-examined: A response to Vinther 2015 (DOI 10.1002/bies.201500018). Bioessays 2015; 37:1174-83. [PMID: 26434749 DOI: 10.1002/bies.201500061] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Round to elongate microbodies associated with fossil vertebrate soft tissues were interpreted as microbial traces until 2008, when they were re-described as remnant melanosomes - intracellular, pigment-containing eukaryotic organelles. Since then, multiple claims for melanosome preservation and inferences of organismal color, behavior, and physiology have been advanced, based upon the shape and size of these microstructures. Here, we re-examine evidence for ancient melanosomes in light of information reviewed in Vinther (2015), and literature regarding the preservation potential of microorganisms and their exopolymeric secretions. We: (i) address statements in Vinther's recent (2015) review that are incorrect or which misrepresent published data; (ii) discuss the need for caution in interpreting "voids" and microbodies associated with degraded fossil soft tissues; (iii) present evidence that microorganisms are in many cases an equally parsimonious source for these "voids" as are remnant melanosomes; and (iv) suggest methods/criteria for differentiating melanosomes from microbial traces in the fossil record.
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Affiliation(s)
- Mary H Schweitzer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.,North Carolina Museum of Natural Sciences, Raleigh, NC, USA.,Department of Geology, Lund University, Lund, Sweden
| | | | - Alison E Moyer
- Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA
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